A network comprises two or more computational systems connected by physical and/or wireless connections. Networks broadly use peer-to-peer or client-server architecture apart from a number of networking protocols for the connected systems to communicate with each other.
Network security is a subgroup of networking. It involves securing the connected network infrastructure from the core to the edge of the network perimeter. Typically managed by a network administrator, network security involves implementing IT security policy and deploying network software and hardware to:
Some of the most common threats to network and computer systems are:
An IT security policy identifies the rules and procedures for all authorized individuals accessing and using an organization's IT assets and resources. It is the principle document for network security. Its goal is to outline rules for ensuring the security of organizational assets.
Employees today often use several tools and applications to conduct business productively. Policy driven by the organization’s culture supports these routines and focuses on safely enabling these tools for employees. Enforcement and auditing procedures for any regulatory compliance to which an organization is subject must be mapped out in the policy as well.
Enforcement concerns analyzing all network traffic flows and should aim to preserve the confidentiality, integrity, and availability of all systems and information on the network. When it comes to enforcing protections, network security operates on a defense-in-depth model and follows the principles of the “CIA” triad:
Strong enforcement strives to provide CIA to network traffic flows. This begins with a classification of traffic flows by application, user and content. As the vehicle for content, all applications must first be identified by the firewall regardless of port, protocol, evasive tactics or encryption. Proper application identification provides full visibility into the content it carries. Policy management can be simplified by identifying applications and mapping their use to a user identity while inspecting the content at all times for the preservation of CIA principles.
The concept of defense in depth is observed as a best practice in network security, prescribing for the network to be secured in layers. These layers apply an assortment of security controls to sift out threats trying to enter the network: access control, identification, authentication, malware detection, encryption, file type filtering, URL filtering and content filtering.
These layers are built through the deployment of firewalls, intrusion prevention systems (IPS) and antivirus components. Among the components for enforcement, the firewall (an access control mechanism) is the foundation of network security.
Providing CIA of network traffic flows is difficult to accomplish with legacy technology. Traditional firewalls are plagued by controls that rely on ports and protocols to identify applications – which have now developed evasive characteristics to bypass the controls – and the assumption that IP address equates to user identity.
Next-generation firewalls retain an access control mission but re-engineer the technology; they observe all traffic across all ports, can classify applications and their content, and identify employees as users. This enables access controls nuanced enough to enforce the IT security policy as it applies to each employee of an organization, with no compromise in security.
Additional services for layering network security to implement a defense-in-depth strategy have been incorporated in the traditional model as add-on components. IPS and antivirus, for example, are effective tools for scanning content and preventing malware attacks. However, organizations must be cautious of the complexity and cost that additional components may add to network security and, more importantly, not depend on these additional components to do the core job of the firewall.
The process of auditing network security requires checking back on enforcement measures to determine how well they have aligned with the security policy. Auditing encourages continuous improvement by requiring organizations to reflect on the implementation of their policy on a consistent basis. This gives organizations the opportunity to adjust their policy and enforcement strategy in areas of evolving need.
Firewalls, IPS, network access control (NAC), and security information and event management (SIEM) are the four most essential components of network security. Others include data loss prevention (DLP); antivirus and anti-malware software; application, web and email security; and more.
Network security is essential in protecting networks against data breaches given that virtually all data and applications are connected to a network. Having your network hacked can ruin your organization’s reputation and put you out of business. A good network security system helps businesses mitigate the risk of falling victim of data theft and sabotage.